The Physics of Three-Dimensional Radiation Therapy: Conformal Radiotherapy, Radiosurgery and Treatment Planning (Medical Sciences Series)

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THE PYSHICS OF THREE-DIMENSIONAL RADIATION THERAPY: Conformal Radiotherapy, and Radiosurgery and Treatment Planning......Page 2
CONTENTS......Page 4
PREFACE......Page 7
ACKNOWLEDGEMENTS......Page 10
1.1.1. What is conformal radiotherapy?......Page 12
Table of Contents......Page 0
1.1.2.1. Conventional 2D treatment planning.......Page 14
1.1.2.3. Three-dimensional multimodality medical imaging and 3D treatment planning.......Page 17
1.1.3. The computer system......Page 20
1.1.4. Localization and coordinate systems......Page 21
1.1.5. Structures from images......Page 22
1.1.6. Beams......Page 23
1.1.7. Blocked fields and the beam’s-eye-view......Page 24
1.1.8. Dose calculation......Page 27
1.1.9.1. Methods to display dose distributions; dose-volume histograms.......Page 28
1.1.9.2. Scoring dose plans by ‘regret’.......Page 31
1.1.11.1 Homogeneous irradiation.......Page 33
1.1.11.2.Inhomogeneous irradiation.......Page 35
1.1.11.3.The dose-versus-biological-effect controversy.......Page 38
1.1.11.4. Formal equations of the biological model.......Page 39
1.1.11.5. The time factor and inhomogeneous irradiation.......Page 48
1.2. REGISTRATION OF TWO IMAGE DATASETS FOR 3D TREATMENT PLANNING......Page 49
1.2.1. 3-vector description......Page 52
1.2.2. 4-vector description......Page 54
1.2.3. Decoupling translation from rotation and scaling using centre-of mass coordinates......Page 56
1.2.5.1. Solving for the rotation operator.......Page 57
1.2.5.2. The method of finding the rotation matrix R.......Page 58
1.2.7. Solving by surface-matching method......Page 60
1.2.9. Lock-and-key matching......Page 63
1.2.10. Structure mapping......Page 64
1.3. SUMMARY AND THE NCI STUDY OF 3D RADIATION THERAPY PLANNING......Page 65
REFERENCES......Page 66
2.1. GENERAL CONSIDERATIONS......Page 76
2.2. THE IMPOSSIBILITY OF TRUE INVERSE COMPUTED TOMOGRAPHY......Page 78
2.3. THE CASE OF A CIRCULARLY-SYMMETRIC DOSE DISTRIBUTION......Page 83
2.4. PRIMITIVE BLOCKED ROTATION THERAPY......Page 88
2.5.1. Analytic and iterative deconvolution theory of 2D inverse computed tomography......Page 98
2.5.2. A note on convolution dosimetry based on terma......Page 107
2.5.2.1. Convolution dosimetry by the differential pencil-beam method.......Page 112
2.5.3. Convolution dosimetry by analytic methods based on kerma......Page 114
2.5.3.1. Limitations and gains from the convolution approach.......Page 120
2.5.4. Iterative 2D optimization by simulated annealing......Page 122
2.5.5. Iterative 3D optimization techniques......Page 125
2.5.6. Analytic and iterative deconvolution theory of 3D inverse computed tomography......Page 130
2.5.7. The inversion algorithm for proton therapy......Page 132
2.6. SUMMARY......Page 135
2.7. APPENDIX 2A. A HISTORICAL NOTE ON THE ORIGINS OF ROTATION THERAPY......Page 136
REFERENCES......Page 138
3.1.1. Stereotactic positioning devices......Page 146
3.2. RADIOSURGERY AND STEREOTACTIC RADIOTHERAPY......Page 155
3.2.1. Radiosurgery with 60Co sources; the gamma knife......Page 156
3.2.2. Stereotactic multiple-arc radiotherapy with a linear accelerator......Page 161
3.2.2.1. Dynamic stereotactic radiosurgery.......Page 166
3.2.2.2. The dose calculation algorithm in linac-based stereotactic radio- surgery.......Page 168
3.2.2.3. Dynamic collimation for stereotactic radiosurgery with multiple arcs.......Page 170
3.2.4. Comparison of different radiation types and geometries......Page 171
3.3. STEREOTACTIC INTERSTITIAL IMPLANT THERAPY......Page 174
3.4. SUMMARY......Page 175
REFERENCES......Page 176
4.1. INTRODUCTION: ELEMENTARY PHYSICS OF PROTON BEAMS......Page 183
4.1.1. Protons for clinical problems......Page 187
4.2. PROTON-THERAPY FACILITIES......Page 190
4.3. RANGE MODULATION AND PRODUCTION OF LARGE-AREA BEAMS......Page 197
4.3.1. Spreading out the Bragg peak......Page 198
4.3.2. Theory of flattening proton dose distributions for large-field radiotherapy......Page 201
4.3.3. spot scanning......Page 205
4.3.4. Monitoring the beam intensity......Page 207
4.4.1. Tomographic imaging for proton treatment planning......Page 209
4.4.2. Theory of range modulation by compensator or bolus......Page 211
4.4.3. Theoretical treatment of thin inhomogeneities......Page 216
4.4.4. The dose-perturbing effect of thick inhomogeneities......Page 220
4.4.5. The differential pencil-beam model for proton dose calculation......Page 221
4.5. SUMMARY......Page 223
REFERENCES......Page 224
5.1.1. Early history......Page 229
5.2.1. Brahme\'s patent......Page 234
5.2.2. Ishigaki’s MLC......Page 236
5.2.3. Heidelberg’s MLCs......Page 238
5.2.4. Kobayashi’s MLC......Page 239
5.2.7. Uchiyama\'s MLC......Page 242
5.2.9. Biggs\' MLC......Page 243
5.3. BRAHME’S THEORY OF ORIENTATION......Page 244
5.4. OPTIMIZED BEAM PROFILES......Page 246
5.5. HOW THE LEAF POSITIONS MAY BE DETERMINED......Page 248
5.6.1. The Varian MLC......Page 249
5.6.2. The Philips MLC......Page 250
REFERENCES......Page 252
6.1. THE NEED FOR HIGH-QUALITY PORTAL IMAGING......Page 257
6.2. FLUOROSCOPIC DETECTORS......Page 258
6.3. SCANNING LINEAR ARRAY OF DIODES AND CRYSTAL DETECTORS......Page 265
6.4. MATRIX IONIZATION-CHAMBER DETECTORS......Page 270
6.5.1. Film digitization......Page 275
6.5.2. Influence of metal screens......Page 276
6.5.3. Film enhancement by analogue processing......Page 281
6.6. IMAGING WITH A PHOTOSTIMULABLE PHOSPHOR PLATE (FUJI SYSTEM)......Page 282
6.7. PORTAL IMAGING BY RECONSTRUCTING FROM PROJECTIONS......Page 284
6.8. PORTAL IMAGING BY XERORADIOGRAPHY......Page 285
6.9. SOLID-STATE IMAGERS......Page 286
6.10. DIAGNOSTIC IMAGING ON A LINEAR ACCELERATOR......Page 287
6.11. THEORETICAL CONSIDERATIONS OF DOSE AND IMAGE SIGNAL-TO-NOISE RATIO......Page 288
6.12. PORTAL DOSE IMAGES; TRANSIT DOSIMETRY......Page 289
6.13. MEGAVOLTAGE COMPUTED TOMOGRAPHY......Page 291
6.14. SUMMARY......Page 292
REFERENCES......Page 294
7.1. THE EARLIEST TREATMENT MACHINE FOR CONFORMAL THERAPY WITH A 137CS SOURCE......Page 301
7.2. TRACKING UNITS......Page 302
7.3. A TRACKING LINAC WITH MULTILEAF COLLIMATOR AND CT COMBINATION......Page 303
7.4. THE UNIVERSAL WEDGE FOR THE LINEAR ACCELERATOR......Page 304
7.5. THE DYNAMIC WEDGE FOR THE LINEAR ACCELERATOR......Page 306
7.7. LINEAR ACCELERATORS WITH INDEPENDENT COLLIMATORS......Page 308
7.8. TWO-DIMENSIONAL TISSUE COMPENSATORS......Page 310
7.9. SUMMARY......Page 313
REFERENCES......Page 314
8.1. INTRODUCTION......Page 317
8.2. PRINCIPLES OF IMAGING BY COMPUTED TOMOGRAPHY......Page 318
8.3. X-RAY COMPUTED TOMOGRAPHY......Page 322
8.4. MAGNETIC RESONANCE IMAGING......Page 324
8.5. ULTRASOUND IMAGING......Page 327
8.7. POSITRON EMISSION TOMOGRAPHY-PET......Page 328
8.8.1. Systems for non-diagnostic computed tomography (NDCT)......Page 329
8.8.2. NDCT on a simulator with an image intensifier as detector......Page 330
8.8.3. NDCT with multiwire or scintillation detector......Page 333
8.8.4. The Royal Marsden Hospital CT Simulator......Page 335
8.8.5. Cone-beam x-ray CT on a simulator......Page 337
8.9. SUMMARY......Page 338
REFERENCES......Page 339
EPILOGUE......Page 346
APPENDIX A: NUMERICAL QUESTIONS......Page 348
REFERENCES......Page 352
APPENDIX B: GLOSSARY OF TERMS......Page 353
APPENDIX C: IMPORTANT DEVELOPMENTS IN ‘SUPERVOLTAGE’ RADIOTHERAPY FOR CONTEXTUAL FRAMING OF CONFORMAL RADIOTHERAPY......Page 365
REFERENCES......Page 367
FURTHER READING FOR PRE-SUPERVOLTAGE RADIOTHERAPY......Page 368